Question

A student is added to few pieces of aluminium metal to two testvtubes a and b containing aqueous solution of iron sulphate and copper sulphate. In the second part of her experiment she added iron metal to another test tubes c and d containing aqueous solution of aluminium sulphate and copper sulphate .In which test tube or test tubes will she observes colour change ? On the basis of this experiment state which one is the mostvreactive metal and why

Answer 1

test tube A : Al + FeSO4 ------>Al2(SO4)3 + Fe

pale green solution of feso4 fades to form colourless solution of Al2(SO4)3 reddish deposits of Fe is formed over Al

test tube B : Al + CuSO4 ------->Al2(SO4)3 + Cu

pale blue colour of the CuSO4 fades to form colourless solution of Al2(SO4)3 reddish brown deposits of Cu is formed over Al.

what is added to the test tube is not mentioned in the question . It seems that it is Fe

test tube C :Fe + Al2(SO4)3 --------> no reaction

since iron is less reactive than al it cannot displace Al from its salt solution.

test tube D : Fe + CuSO4 ------->FeSO4 + Cu

pale blue solution of CuSO4 changes to form pale green solution of FeSO4 and reddish brown deposits of Cu is formed over Fe.

From this we can conclude that reactivity is Al > Fe > Cu because it can displace Fe and Cu from their salt solution.

So Al is most reactive.......................................................  

balance equation.